[llvm-dev] Need help with code generation

[David Blaikie via llvm-dev]

On Mon, Mar 21, 2016 at 4:35 PM, Rafael Espíndola <
rafael.espindola at gmail.com> wrote:

>
> On Mar 21, 2016 5:49 PM, "David Blaikie" <dblaikie at gmail.com> wrote:
> >
> >
> >
> > On Mon, Mar 21, 2016 at 2:46 PM, Rafael Espíndola <
> llvm-dev at lists.llvm.org> wrote:
> >>
> >> On 21 March 2016 at 17:34, Tim Northover via llvm-dev
> >> <llvm-dev at lists.llvm.org> wrote:
> >> >> My understanding is that clang and llvm themselves are designed this
> way
> >> >> (crash when the unexpected happens).
> >> >
> >> > I don't think so. I'd view any Clang crash as a bug (probably to be
> >> > prioritised below silent CodeGen and many others, but not "working as
> >> > designed").
> >> >
> >> >> For example the fact that clang forks itself to be able to report
> diagnostics
> >> >
> >> > That seems like just trying to make our own job easier to me. I think
> >> > the entire point of the fork is to get a backtrace we can fix, and
> >> > point out where the user should send it.
> >> >
> >> >> llvm is full of report_fatal_error() (or worse, assertions that can
> fire on unexpected user input).
> >> >
> >> > A bit of a grey area since LLVM isn't itself a user-facing tool, but I
> >> > think I'd still say that a report_fatal_error that's not actionable by
> >> > the user is actually an LLVM bug. And a segfault definitely so.
> >>
> >> It is completely trivial to crash llvm. A case I wrote today in
> >> another thread while waiting for tests to run:
> >>
> >> target triple = "x86_64-unknown-linux-gnu"
> >> @".data" = global i32 42
> >>
> >> That will crash "llc -filetype=obj". The fact that it is considered a
> >> bug doesn't mean much if there is no coordinated effort to fix them.
> >
> >
> > I think it does, actually - that patches will be accepted to fix pretty
> much any crash in LLVM. (llc isn't a user facing tool, so that's a
> praticularly low priority -
>
> I am pretty sure clang crashes if you translate the above example to C.
>
> Philosophical question: what is the difference of a non bug and a bug of
> such low priority that it is never fixed?
>
 One where contributors are encouraged to provide patches to fix things,
versus one where contributors are told that there is a high bar to get such
a patch contributed seems like a pretty big difference to me.

It changes who's willing to contribute to the project, or build tools based
on it.

- David
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20160321/261f519a/attachment.html>